Scope of the Palladium-Catalyzed Aryl Borylation Utilizing Bis-Boronic Acid
作者:Gary A. Molander、Sarah L. J. Trice、Steven M. Kennedy、Spencer D. Dreher、Matthew T. Tudge
DOI:10.1021/ja303181m
日期:2012.7.18
wasteful reagents to prepare boronic acid derivatives and require additional steps to afford the desired boronic acid. The scope of the previously reported palladium-catalyzed, direct boronic acid synthesis is unveiled, which includes a wide array of synthetically useful aryl electrophiles. It makes use of the newly available second generation Buchwald XPhos preformed palladium catalyst and bis-boronic
Cross-Coupling Reactions of Halopurines with Aryl- and Alkyltrifluoroborates; The Scope and Limitations in the Synthesis of Modified Purines
作者:Michal Hocek、Zbyněk Hasník、Radek Pohl
DOI:10.1055/s-0028-1088038
日期:2009.4
The scope and limitations of the use of the palladium-catalyzed cross-couplingreactions of diverse alkyl- and aryltrifluoroborates with halopurines have been studied. While aryl- and hetaryltrifluoroborates reacted readily with both 6-chloropurines and 8-bromoadenines to give the corresponding 6- or 8-aryl derivatives in high yields, the alkyltrifluoroborates were much less reactive and, even after
The 1,3-Diaminobenzene-Derived Aminophosphine Palladium Pincer Complex {C6H3[NHP(piperidinyl)2]2Pd(Cl)} - A Highly Active Suzuki-Miyaura Catalyst with Excellent Functional Group Tolerance
作者:Jeanne L. Bolliger、Christian M. Frech
DOI:10.1002/adsc.200900848
日期:——
The rapidly prepared 1,3‐diaminobenzene‐derived aminophosphine pincer complex C6H3[NHP(piperidinyl)2]2Pd(Cl)} (1) is an effective Suzuki catalyst with excellentfunctionalgrouptolerance. Side‐product formations, such as homocoupling, debromation or protodeboration have only rarely been detected and if so, were in all cases below the 5% level. The presented reaction protocol is universally applicable
快速制备的1,3-二氨基苯衍生的氨基膦钳形配合物C 6 H 3 [NHP(哌啶基)2 ] 2 Pd(Cl)}(1)是一种有效的Suzuki催化剂,具有出色的官能团耐受性。仅很少检测到副产物形成,例如均偶联,去溴化或原去硼,如果这样,在所有情况下均低于5%的水平。提出的反应方案是普遍适用的。实验观察表明,钯纳米颗粒的催化活性形式1。
Noncovalent inhibition of the serine proteases, α-chymotrypsin and trypsin by trifluoro(organo)borates
作者:Reem Smoum、Abraham Rubinstein、Morris Srebnik
DOI:10.1039/b415957h
日期:——
A series of potassium organotrifluoroborates were synthesized. Their stability to hydrolysis was determined in D2O, TRIS and phosphate buffer. It was found that in both D2O and TRIS buffers, these compounds are quite stable, whereas in phosphate buffer rapid hydrolysis occurs. Based on these results, a study was undertaken to determine whether potassium organotrifluoroborates can serve as protease inhibitors. It was found that potassium organotrifluoroborates increased inhibition by at least an order of magnitude over the corresponding boronates. Dixon plots showed that these compounds are reversible competitive inhibitors of α-chymotrypsin and trypsin. Based on 19F NMR, we speculate that they inactivate the enzymes as a result of the formation of hydrogen-bonds between fluorine atoms of the inhibitors and the serine protease.
合成了一系列有机三氟硼酸钾。测定了它们在 D2O、TRIS 和磷酸盐缓冲液中的水解稳定性。结果发现,在 D2O 和 TRIS 缓冲液中,这些化合物都相当稳定,而在磷酸盐缓冲液中则会发生快速水解。基于这些结果,研究人员开始研究有机三氟硼酸钾是否可以作为蛋白酶抑制剂。研究发现,与相应的硼酸盐相比,有机三氟硼酸钾的抑制作用至少增加了一个数量级。狄克逊图显示,这些化合物是δ-糜蛋白酶和胰蛋白酶的可逆竞争抑制剂。根据 19F NMR,我们推测它们之所以能使酶失活,是因为抑制剂的氟原子与丝氨酸蛋白酶之间形成了氢键。